Methods for producing sucralose intermediates and sucralose from a feed stream comprising a sucrose-6-acylate in a reaction vehicle are known. For example, EP 0409549 discloses a process for the chlorination of a sucrose-6-acylate in a tertiary amide reaction vehicle to produce a sucralose-6-acylate, such as sucralose-6-acetate. A large excess of an acid chloride, such as phosgene, is used as the chlorination agent in this process. Following the chlorination reaction, the excess chlorinating agent is quenched using a suitable base, thereby forming the chloride salt of the base. The resulting product stream thus comprises a sucralose-6-acylate, the tertiary amide reaction vehicle, water, and salts.
A known method for obtaining sucralose from a product stream comprising a sucralose-6-acylate, a tertiary amide reaction vehicle, water, and salts, without isolation of the sucralose-6-acylate intermediate, is disclosed in EP 0708110. The process comprises deacylation of the sucralose-6-acylate before or after removal of the tertiary amide reaction vehicle, and then isolation of the sucralose. The removal of the tertiary amide (which is usually dimethylformamide [DMF]) is carried out by steam stripping. Other methods of extraction of sucralose are known, for example, in U.S. Pat. No. 8,212,022.
Methods for preparing sucrose-6-acylate starting materials for chlorination to sucralose-6-acylate are known, for example, in U.S. Pat. No. 4,950,746; U.S. Pat. No. 4,889,928; U.S. Pat. No. 5,023,329; U.S. Pat. No. 5,089,608; U.S. Pat. No. 5,034,551; U.S. Pat. No. 5,470,969; U.S. Pat. No. 5,440,026; U.S. Pat. No. 6,939,962; and US 2007-0227897.
Other methods of chlorinating sucrose-6-acylate to give sucralose-6-acylate are known, for example, in U.S. Pat. No. 4,380,476; US 2006-0205936; U.S. Pat. No. 7,932,380; and US 2007-0100139.
When a tertiary amide such as DMF is used as a reaction solvent for chlorination, it is known to include a co-solvent in the reaction medium, for example, in US 2011-087018; WO 2011-045565; US 2012-0077972; and US 2012-0095199; as well as in EP 0409549.
Further methods of chlorinating carbohydrates such as sucrose-6-acylates are known in WO 2012/071385 and WO 2013/056128. These two documents disclose a variety of solvents and co-solvents for the chlorination of carbohydrates.
Although methods of making sucralose, and of chlorinating sucrose-6-acylate to give sucralose-6-acylate, are known, there may remain scope to modify the chlorination reaction.